Backbone cyclization is often used in attempts to enhance protein stability, but is not always successful as it is possible to remove stabilizing or introduce destabilizing interactions in the process. Cyclization of the PIN1 WW domain, a 34-residue three-stranded beta-sheet structure, removes a favorable electrostatic interaction between its termini. Nevertheless, optimization of the linker connecting the N- and C-termini using information based on the previously determined ensemble of NMR structures leads to beta-sheets that are more stable than those derived from the linear sequence. Linkers that are too short or too long introduce strain, likely disrupting native interactions, leading to cyclic folds that are less stable than that of the linear sequence.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/ja0123608 | DOI Listing |
Adv Sci (Weinh)
January 2025
Jihua Hengye Electronic Materials Co. Ltd., Foshan, Guangdong, 528200, P. R. China.
B- and N-heterocyclic fluorophores have reveal promising efficiency in blue organic light-emitting diodes (OLEDs) with small full-width-at-half-maximum (FWHM). However, their structural determinants for spectral broadening and operating stability are still needed to be investigated in further. Herein, a novel multi-N-heterocycles Diindolo[3,2,1jk:3',2',1'jk]dicarbazole[1,2-b:4,5-b] (DIDCz) is proposed to manipulate the emission color toward pure blue region by extending π-conjugation of the N-π-N bridge.
View Article and Find Full Text PDFbioRxiv
December 2024
Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot, Oxfordshire, UK.
Conjugation, the major driver of the spread of antimicrobial resistance genes, relies on a conjugation pilus for DNA transfer. Conjugative pili, such as the F-pilus, are dynamic tubular structures, composed of a polymerized pilin, that mediate the initial donor-recipient interactions, a process known as mating pair formation (MPF). IncH are low-copy-number plasmids, traditionally considered broad host range, which are found in bacteria infecting both humans and animals.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, United States.
Diaryl thieno-[3,4-]thiophenes (TT) are photoswitchable compounds that operate through reversible photoinduced cyclization/cycloreversion and have been designed specifically for integration within π-conjugated polymers to switchably manipulate polymer electronic properties. Here we report on how cross conjugating the central TT moiety impacts photocyclization dynamics as interrogated using transient absorption spectroscopy (TAS) for a series of switches built with electron-rich substituents that have various electronic interaction strengths with the TT core. For cross-conjugated structures exhibiting a propensity to switch in steady-state photoconversion experiments, ultrafast TAS reveals signatures of rapid dynamics (occurring within <1-10 ps) similar to those observed for unsubstituted switches and that are consistent with photocyclization.
View Article and Find Full Text PDFJ Biol Chem
December 2024
Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, Ames, Iowa, USA. Electronic address:
The citrus scent arises from the volatile monoterpene limonene, whose cyclic nature can be viewed as a miniaturized form of the polycyclic sterol triterpenoids. In particular, these rings are all formed from poly-isoprenyl precursors via carbocation cascades. However, the relevant reactions are initiated by distinct mechanisms, either lysis/ionization of an allylic diphosphate ester bond, as in limonene synthases, or protonation of a terminal olefin or epoxide, as in lanosterol synthases.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Department of Chemistry, The University of Western Ontario, 1151 Richmond St., London, Ontario, N6 A 5B7, Canada.
The development of polymers from renewable resources is a promising approach to reduce reliance on petrochemicals. In addition, depolymerization is attracting significant attention for the breakdown of polymers at their end-of-life or to achieve specific stimuli-responsive functions. However, the design of polymers incorporating both of these features remains a challenge.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!